Sun Shougang, Wan Ziqi, Xu Yingying, Zhou Xuemei, Gao Wei, Qian Jinjie, Gao Jie, Cai Dong, Ge Yongjie, Nie Huagui, Yang Zhi
Key Laboratory of Carbon Materials of Zhejiang Province, Institute of Industrial Carbon Materials and Hydrogen Energy Technology of Wenzhou University, Wenzhou University, Wenzhou 325035, China.
State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China.
ACS Nano. 2025 Apr 1;19(12):12090-12101. doi: 10.1021/acsnano.4c18288. Epub 2025 Mar 20.
The engineering of dual-functional catalytic systems capable of driving complete water dissociation in acidic environments represents a critical requirement for advancing proton exchange membrane electrolyzer technology, yet significant challenges remain. In this work, we investigate an IrO/MoS/CNT heterostructure catalyst demonstrating enhanced bifunctional performance for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) under acidic conditions. Strategic incorporation of IrO into the MoS/CNT heterojunction induces a partial phase transformation from 2H to the metastable 1T configuration in MoS, thereby modulating the electronic structure of IrO and improving the catalytic performance for overall water splitting. The optimized IrO/MoS/CNT catalyst exhibited exceptional overpotentials of 9 mV (HER) and 182 mV (OER) at a current density of 10 mA cm in acidic media. Full-cell evaluations further confirmed its practical potential, showing a 1.47 V operation voltage that outperforms standard Pt/C||IrO counterparts by 120 mV. The experimental results revealed that the n-n heterojunction between IrO/CNT and MoS/CNT generates a built-in electric field, enhancing charge redistribution and electron transport. Moreover, density functional theory simulations further identify iridium centers as dominant catalytic loci, with a metastable 1T-MoS phase mediating charge equilibration at atomic interfaces. This modification facilitates *OH adsorption and *OOH deprotonation and lowers the kinetic barrier during the water-splitting process.
能够在酸性环境中驱动水完全解离的双功能催化系统的工程设计是推动质子交换膜电解槽技术的关键要求，但仍存在重大挑战。在这项工作中，我们研究了一种IrO/MoS/CNT异质结构催化剂，该催化剂在酸性条件下对析氧反应（OER）和析氢反应（HER）均表现出增强的双功能性能。将IrO策略性地引入MoS/CNT异质结中，会诱导MoS中从2H到亚稳1T构型的部分相变，从而调节IrO的电子结构并提高整体水分解的催化性能。优化后的IrO/MoS/CNT催化剂在酸性介质中，电流密度为10 mA cm时，表现出9 mV（HER）和182 mV（OER）的优异过电位。全电池评估进一步证实了其实际潜力，显示出1.47 V的工作电压，比标准的Pt/C||IrO对应物高出120 mV。实验结果表明，IrO/CNT和MoS/CNT之间的n-n异质结产生了内建电场，增强了电荷重新分布和电子传输。此外，密度泛函理论模拟进一步确定铱中心为主要催化位点，亚稳的1T-MoS相在原子界面介导电荷平衡。这种修饰促进了OH吸附和OOH去质子化，并降低了水分解过程中的动力学势垒。
